JUMPING OFF POINT: Brook Lopez wins the tip-off in the Nets’ first regular-season game in Brooklyn last night, a 107-100 victory against the Raptors at Barclays Center. Photo: Charles Wenzelberg/New York Post

It wasn’t the opening night opponent the Nets spent months planning for. But, in the end, it didn’t matter.

Major-league sports officially returned to Brooklyn Saturday night, ending a 55-year wait for a borough that still feels the pain of the Dodgers leaving town. Finally, the borough has a team to call its own.

They have the Nets, who opened their season — and a new era for the franchise — with a 107-100 win over the Raptors last night in front of a sellout crowd of 17,732 inside Barclays Center.

“This was such a huge night,” Nets coach Avery Johnson said. “And if I give you a list of reasons why, we’d probably be here for a while.

“But let’s just start with the fact that we’re in Brooklyn now, and it’s a big difference.”

In many ways, it is a fitting match: a borough that has longed for a team to call its own and a franchise that has never quite found the home it has always longed for. As the Nets have waited for this move to become reality, the team has wallowed in obscurity in recent years, playing in front of a fan base in New Jersey that had little reason to cheer for a team about to abandon them.

But the Nets had the power of a borough fully behind them last night, and particularly late in the fourth quarter, when the crowd — most of whom were wearing black and white — serenaded the players with a deafening chant of “Brook-lyn! Brook-lyn!”

“I love the chant,” said Joe Johnson, who finished with 14 points, five rebounds and four assists. “That gave me chills. I know that these fans want the best for this team, and all they want from us is to work hard and give them a show.”

The curtain came up on that show for the first time with part-owner Jay-Z and wife Beyonce sitting courtside and billionaire owner Mikhail Prokhorov watching from high above in his luxury suite. And, after committing over $300 million to reshape a roster that went 22-44 last season, Prokhorov has higher aspirations for his team than simply making the playoffs.

“You know, just good play, and maybe [the Eastern] Conference Finals,” he said with a smile when asked what he would consider a successful season during his pregame press conference.

But in the first quarter, the Nets looked much more like the team they had been the past few seasons than the one they hope to be, allowing the Raptors to shoot a blistering 15-for-24 (63 percent) from the field and take a 35-27 lead.

Things quickly changed for the Nets, however, once they put in their second unit to start the second quarter. Behind stellar shooting from C.J. Watson, who had 10 points in the quarter and 13 in the first half, and a sterling group defensive effort, the Nets began the quarter on a 13-3 run over the first 5:21 to retake the lead at 40-38. Most of the starters then returned and pushed the lead to 60-52 at halftime, capping the half with a Deron Williams drive and dish to Watson for a 3-pointer from the left wing as time expired that sent the crowd into a frenzy.

“We had a feeling that the environment was going to be great inside the arena once the season started,” said Williams, who finished with 19 points and nine assists. “Having a team back in the borough, and we’re just excited to be here.”

But after the Nets stretched the lead to as many as 14 points in the third quarter, they didn’t put the Raptors away. Toronto battled back, cutting the lead to two with 3:09 left in the game on a bucket from guard DeMar DeRozan, and then again with just over a minute left.

Gerald Wallace then found Brook Lopez, who finished with a team-high 27 points, with a picture-perfect pass under the basket. Lopez converted the layup and the ensuing free throw to seal an opening-night win and set off a party inside the Nets’ new home.

“It was a great night,” Williams said, “capped off by a win, which is what we want.”